(Reuters) - Japan's Toray Industries Inc (3402.T), maker of advanced fibers used in Boeing Co's (BA.N) 787 Dreamliner jet, will buy U.S.-based Zoltek Companies Inc ZOLT.O in a move to tap into the lower end of the growing global market for carbon fibers.

The agreed $584 million deal will give Toray, also developing high-specification fibers for luxury auto maker Daimler AG (DAIGn.DE), access to Zoltek products used to make construction materials and cheaper auto parts.

Carbon fiber is strong and lighter than steel, but higher prices have restricted its appeal to potential customers so far.

Under terms of the transaction, Toray will acquire all of Zoltek's outstanding shares for $16.75 per share in cash. The offer was unanimously approved by Zoltek's board, isn't subject to any financing conditions and is expected to close late this year or early in 2014.

Toray's offer represents a 2 percent premium to Zoltek's closing price on Wednesday of $16.43. Zoltek's stock closed up 12.6 percent at $18.51 on Thursday after the Nikkei business daily reported the news, giving a range of $600-$700 million for the acquisition.